Method of coloring citrous fruits



load of fruit.

Patented Dec. 45, 1923.

f Ween FRANK n nann or Los enemas, camromqm, DEDICATED, BY mnsnn ASSIGN- MENTg, To THE CITIZENS on THE UNITED STATES.

METHOD OF COLORING CITROUS FRUITS.

No Drawing.

Application filed March 1, 1923. Serial No. 622,156.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L, 625.)

the United States or any of its officers or employees in the prosecution of work for the Government, or by any person in the United States, without payment to me ot" any royalty thereon.

The process of curing lemons as heretofore carried out has been substantially as follows: The washed and sorted fruit is laced in packing boxes containing from to 60 lbs.v of fruit each. These are stacked in rooms which contain approximately a car- Blue flame kerosene stoves are installed either in the room, in the basement beneath the room or in an outside stove house. These stove houses, or generating rooms as they are often called, contain from 6 to 30 stoves. The gases generated in this room are conveyed through pipes into the rooms where the fruit is stored. The humidity in each case is controlled by water placed upon the stoves, whether they are in the generating room, in the basement or in the storage room. Storage rooms are usually so constructed as to be easily ventilated. In this way fruit has been cured in from 5 to 15 days, depending upon the original color of the fruit, the temperature of the room and apparently, to some extent, upon the number of burners operated.

Myinvestigations have led, through the analyses of these combustion gases, to the selection of the gas known as ethylene (C l-I asbein mainly responsible for the coloring of the ruit. I have found that carbon monoxide, acetylene and possibly some other constituents, including butadiene, also have the power of coloring citrous fruits.

Ethylene, however, brings about the change product which can be readily secured in cylinders has also led to its selection as the best means for accomplishing the result.

In the practical operation of my process, ethylene gas from a cylinder is liberated into the room by means of a pipe leading from the cylinder through the walls-of the room, or the gas cylinder is carried into the room, the cubic content of which has been ascertained, and a sufiicient amount of gas liberated to bring the content in the room to the desired amount. It is preferred to renew the gas from two to four times in twentyfour hours, and to thoroughly ventilate the rooms at least once each day. Where necessary, humidity is maintained by the use of atomizers. It is found that the coloring of the fruit will take place slowly at temperatures as low as F., and develops more rapidly as the temperature is increased. So far as the experiments go, a temperature of 65 to 70 F. seems most favorable for practicalwork, and a temperature of 80 to 85 F. seems to be the maximum for producing the best results. In experiments already'carried out, the practice just described has colored and cured lemons in from 4 to 7 days. Experts passing upon the quality of the fruit could not distinguish it from fruit of the same lots which had been cured by the older method.

The substitution of this new gas method for the older method using stoves will greatly reduce the fire risk, do away with expensive installations of stoves and generating rooms, and will reduce the labor and constant supervision necessary during the operation.v It also permits of a standardized procedure by which uniform results can be obtained, a feature which was entirely lacking under the old method.

While it is not believed that any other of the constituents of combustion gases are as efiicient as ethylene, carbon monoxide and acetylene may be used in the same manner as described above for the use of ethylene.

I claim: 7

A new and useful method of coloring citrous fruits, consisting in bringing ethylene FRANK E. DENNY. 

